N81Vp vs Sager NP8662

1) I honestly don't know if I'll really need the laptop in class that often
2) I have no previous experience with laptops, and so I don't know how it would be to carry a 15.4" 7lb (Sager) or a 14.1" 5.5lb (Asus)
3) I don't know how much gaming I'll be doing. I do play games, but I'm starting to get out of it. I would like to play Dawn of War II and Empire Total War, since my current desktop can't handle them. I'd also like to play Diablo III in the future. I know the Sager will be fine with the 260M GPU, but what about the Asus and its HD 4650?
4) Battery life: From what I've seen, both laptops don't have great battery life. If I can get 2 hours out of the laptop though, while browsing the web, that's fine
5) Whichever laptop I buy WILL be my primary computer. Is a 14.1" fine for writing papers? Watching movies? Browsing the web for extended periods of time?

Thanks =)